Groundwater

All subsurface water, as distinct from surface water.

Groundwater Table

See Reference Groundwater LevelThe reference groundwater elevation..

Grout

(1) Material used to seal pipeline and manhole cracks; also used to seal connections within sewer structures. (2) A material, usually cement based, used to fill the annulus between the existing pipe and the lining; and also to fill voids outside the existing pipeline. (3) A material such as a cement slurry, sand or pea gravel that is pumped into voids.

Grouting

The process of filling voids or modifying/improving ground conditions. GroutingThe process of filling voids or modifying/improving ground conditions. Grouting materials may be cementitious, chemical, or composed of other mixtures. materials may be cementitious, chemical, or composed of other mixtures.

GRP

Glass Reinforced Plastic, a family of rehabilitation linings. Often generically known as Reinforced PlasticAny of a variety of thermoplastic and thermoset material used in sewer construction (e.g., high-density polyethylene, polypropylene, PVC, fiberglass reinforced plastics, polyester felt reinforced pipe, epoxy and polyester mortars, etc). Mortar (RPMReinforced Plastic Mortar; a form of thermoset plastic pipe.) and Reinforced Thermosetting Resin (RTRReinforced Thermosetting Resin; a form of thermoset plastic pipe within the GRP family.).